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Saturn's moon Titan could harbor life, but only a tiny amount

(news.arizona.edu)
61 points geox | 2 comments | 07 Apr 25 21:31 UTC | HN request time: 0.405s | source
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SamBam ◴[10 Apr 25 16:10 UTC] No.43645351[source]▶
I'm interested that their conclusion -- that Saturn could only support tiny life forms such as bacteria -- is not dependent in any way on the distance from Titan to the Sun.

Am I wrong in thinking that any life must require a steady input of energy, and that this must come from either solar energy or geothermal energy? Quick Googling says that Titan's core isn't known for sure, but probably isn't very hot.

If Titan's life were dependent of solar energy, wouldn't it's distance from the Sun imply very little energy to go around, and so very unlikely to have large organisms?

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1. Symmetry ◴[10 Apr 25 18:24 UTC] No.43646722[source]▶
Life on Earth was dependent on chemosythesis for the better part of a billion years before photosynthesis was developed. Photosynthesis is really very complex so I think we can rule that out as an initial form of life.

Hydrothermal vents are a great source of chemical energy in the form of hydrogen, hydrogen sulfide, or other chemicals that can be reacted for energy where the come out into the sea. But you could imagine other sorts of chemical energy driven by other geologic or atmospheric processes that life might bootstrap from.

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2. adrian_b ◴[11 Apr 25 09:44 UTC] No.43652130[source]▶
The origin of the energy provided by hydrothermal vents is the internal heat of the planet.

The reduced substances, like elemental hydrogen and hydrogen sulfide, are produced by the oxidation of the iron(II) ions from volcanic rocks, which is converted by water into rust.

The volcanic rocks contain this more reduced form of iron, because they come from higher temperatures, where their constituent minerals are in chemical equilibrium. When the volcanic rocks reach ambient temperature, the volcanic rocks are no longer in chemical equilibrium with water. This source of chemical energy powers the hydrothermal vents and the associated life.

So the conditions for the appearance of life are an internal source of heat in the planet or satellite and some form of volcanism that can bring substances from the hot deep interior to the cold surface.